The sea jellyfish, which is called a wasp, belongs to the category of box jellyfish, a type of cnidarians. She is a representative of the exceptional animals of the marine world and is able to live only in the salt water of the seas and oceans.
Invisible danger
The sea wasp jellyfish is considered the most poisonous jellyfish in the world. The toxin that is released from its tentacles depresses nervous system, causes severe burns and unbearable pain. The result is a heart attack that can lead to cardiac arrest. Timely medical assistance in some cases can save a person’s life. However, there are known cases of death within a very short period of time after an encounter with a poisonous monster. Even a dead sea wasp (photo below) is a source of increased danger. The poison-toxin disintegrates only a week after the death of the jellyfish, so it is strictly forbidden to touch it.
Unfortunately, jellyfish of this species are also found in places beach resorts and diving sites. Another danger of meeting a sea wasp is that it is almost invisible. Therefore, precautions should not be neglected.
Habitat
The jellyfish is found in the Indo-Western Pacific Ocean and in Southeast Asia. Most often, the sea wasp is found near the coast of northern Australia, where there are many corals and shallow sea depths. summer months from November to March. Jellyfish inhabit coastal areas at a respectful distance from the coast, but when the sea is very rough they can be washed ashore.
Appearance
The sea wasp is the most major representative of his class. The body of the jellyfish is a transparent dome, consisting of 95% water. Its shape is similar to a rounded cube, hence the name box jellyfish. The size of the dome is 20-45 cm, in size it can be compared with a basketball ball. It has a pale blue color and is completely invisible in the water.
The animal has 24 eyes, which are located in three pairs in each corner of the dome. Two pairs of eyes serve to receive images, and one only reacts to light. Scientists cannot explain the presence of so many eyes in a jellyfish, because the information received from what it sees has nowhere to be transmitted; it does not have a brain.
In addition to the organs of vision, there are 60 tentacles - four bundles of 15 pieces each. The probes, 15 cm long and 5 mm thick, stretch up to three meters when hunting for prey. Each tentacle is covered with stinging cells containing deadly poison.
The sea wasp does not have a skeleton; it is replaced by two nervous systems, one of which receives and processes information received from the organs of vision, and the other controls the movement of muscles along the border of the dome, which function simultaneously and harmoniously.
Nutrition
Sea wasps feed in coastal waters on small fish and various bottom organisms, but their most favorite delicacy is shrimp. When going out to fish, they extend their tentacles and freeze in place. The jellyfish encloses the stalked victim in probes, pierces the skin, injects poison, kills and swallows. In appearance, its bite resembles a wasp, only the venom is much more toxic, incomparable even to the venom of a snake.
Reproduction
The sea wasp gives birth only once in its entire life, and then dies. Box jellyfish live for about 7 months and continue to grow throughout this period.
Sea wasps reproduce offspring in the same way as other individuals belonging to this species. They breed in the summer, gathering in large flocks and swimming closer to the shores. During this period of time, Australia is trying to close all beaches.
The male ejects a dose of sperm into the water while near the swimming female. The latter swallows it, fertilization occurs. Larvae develop inside the female, which after some time are released into the water and settle on the surface of the seabed. They stick to stones, shells, and driftwood, forming polyps.
As a result of budding, small jellyfish grow from polyps, which break off and begin an independent life. They immediately navigate the sea and feed on plankton on their own.
What do Australians call a sea wasp?
Due to its transparency, this small sea animal is almost invisible in the water. It is an active predator and poses a great danger to animals and humans. This animal swims well and maneuvers well among algae and corals, moving at speeds of up to six meters per minute. During the day it is most often at the bottom, and with the onset of evening it floats to the upper layers of water. The speed at which a jellyfish attacks its prey is very high.
And the poison contained in the tentacles is so poisonous that when stung, any creature instantly dies. Moreover, it stings several times in a row, bringing the concentration of poison to a lethal level. Australian sea wasp - that’s what this jellyfish is called - it poses a danger to all living organisms, with the exception of the poison of these predators does not affect them, and turtles eat box jellyfish with appetite.
Consequences of an encounter with a sea wasp
Although box jellyfish are extremely dangerous to human life, they do not attack them themselves; on the contrary, they tend to swim to the side. It can sting a person purely by accident. Often the victims are scuba divers who are not protected by special suits.
When the skin comes into contact with the tentacle, terrible pain, severe redness and swelling appear. A person's heart most often stops and he drowns. Some managed to get ashore, but paralysis of the respiratory system occurred, and the person died. After autopsy, it was discovered that the victims' respiratory organs were filled with mucus, while others died from cerebral hemorrhage. There were cases where a person did not die immediately, but no one remained alive.
Protecting the lives of vacationers
During the jellyfish migration season, net barriers are installed on beaches to prevent them from entering the swimming area. Despite this, small specimens penetrate through the mesh cells, so the beach administration warns vacationers about the danger and strictly prohibits them from entering the water.
This warning should not be ignored. After all, the fast-acting poison of the sea wasp leaves no hope of salvation. The only way to help is to administer an antidote - antitoxic serum and urgently hospitalize the victim. But this does not give any guarantee of saving life.
- It is known that jellyfish appeared more than 600 million years ago, much earlier than dinosaurs, crocodiles and sharks.
- Jellyfish and polyps are different stages of the life period of the same creature.
- A sea wasp is a jellyfish that breathes through its entire dome and stings like a wasp.
- The absence of a brain does not prevent them from perceiving nervous stimulation from the organs of touch and vision.
- They have two nervous systems.
Jellyfish are able to move underwater by sucking in and expelling water by contracting their parasol muscles, but they mostly drift thanks to the current. Scientists believe that they belong to plankton.
Medusa cannonball
The cannonball jellyfish lives along the east coast of the United States to Brazil. It got its name because of its unusual shape, perfectly smooth and round, like a cannonball. In Asian countries, these jellyfish are widely used in folk medicine. It is believed that they can cure lung disease, arthritis, and lower blood pressure.
Olindias formosa
This rare view jellyfish are found off the coast of Brazil, Argentina, and Japan. Characteristic of these jellyfish is hovering at shallow depths. When the jellyfish is in this state, its tentacles are concentrated under the cap. Due to the small number this type does not pose a danger to people, but we should not forget that they can leave very severe burns.
Portuguese man of war
This amazing creature differs from all jellyfish in that it consists of many jellyfish individuals. It has a gas bubble that floats on the surface of the water, which allows it to absorb air. Tentacles Portuguese man-of-war when extended they can reach 50 meters.
Purple striped jellyfish
This type of jellyfish can be found in Monterrey Bay. They are not yet well studied. This jellyfish has quite big sizes and can cause serious burns to humans. Stripes and rich colors appear in jellyfish as they age. Along with warm currents, the jellyfish can also migrate to the shores of Southern California. This was especially noticeable in 2012, when burns of jellyfish (black sea nettle and purple striped) were received by 130 people.
Mediterranean or jellyfish fried egg
This amazing creature really resembles a fried egg, or poached egg. Jellyfish live in the Mediterranean, Adriatic and Aegean Seas. Her important feature it is believed that she can move independently without relying on waves.
Darth Vader or Narcomedusa
This type of jellyfish was discovered in the Arctic. This happened quite recently. In addition to such an interesting and at the same time terrifying appearance, the jellyfish has 4 tentacles and 12 stomach pouches. While swimming, the tentacles are pulled forward to better reach their prey.
blue jellyfish
The blue jellyfish has very stinging tentacles. It has been discovered off the coast of Scotland, in the North Sea and in the Irish Sea. The average transverse diameter of this jellyfish is 15 centimeters. Color varies from dark blue to bright blue.
Porpit porpit
It's not really a jellyfish. This creature is more commonly known as the blue button. The porpet lives on the surface of the ocean and consists of two parts: a hard golden-brown float and hydroid colonies, which in appearance are very similar to the tentacles of a jellyfish. Porpita can easily be confused with a jellyfish.
Diplulmaris Antarctica
This magnificent creature lives in the deep waters of Antarctica and has four bright orange tentacles as well as white tentacles. The small white dots on the jellyfish are side-spreads. They live inside the jellyfish and sometimes even feed on it.
Black sea nettle
The black sea nettle is a giant bell-shaped jellyfish with a diameter of 3 feet. An adult can reach 5 meters and have 24 tentacles. This type of jellyfish was discovered in the waters Pacific Ocean. they are carnivores. They prefer larvae, plankton, and other jellyfish as food.
Among the most unusual animals on Earth, jellyfish are also among the oldest, with an evolutionary history dating back hundreds of millions of years. In this article, we reveal 10 basic facts about jellyfish, from how these invertebrates move through deep water to how they sting their prey.
1. Jellyfish are classified as cnidarians or cnidarians.
Named after the Greek word for "sea nettle," cnidarians are marine animals characterized by a jelly-like body structure, radial symmetry, and stinging "cnidocyte" cells on their tentacles that literally explode when capturing prey. There are about 10,000 species of cnidarians, about half of which are classified as coral polyps, and the other half include hydroids, scyphoids, and box jellyfish (the group of animals most people call jellyfish).
Cnidarians are among the most ancient animals on earth; Their fossil roots go back almost 600 million years!
2. There are four main classes of jellyfish
Scyphoid and box jellyfish are two classes of cnidarians that include classical jellyfish; The main difference between the two is that box jellyfish are cube-shaped and bell-shaped, and are slightly faster than scyphoid jellyfish. There are also hydroids (most species of which do not go through the polyp stage) and staurozoa - a class of jellyfish that lead a sedentary lifestyle, attaching to a hard surface.
All four classes of jellyfish: scyphoid, box jellyfish, hydroid and staurozoa belong to the subphylum of cnidarians - medusozoa.
3. Jellyfish are some of the simplest animals in the world
What can you say about animals without central nervous, cardiovascular and respiratory systems? Compared to animals, jellyfish are extremely simple organisms, characterized mainly by wavy bells (which house the stomach) and tentacles containing many stinging cells. Their almost transparent bodies consist of only three layers of outer epidermis, middle mesoglea, and inner gastrodermis and water making up 95-98% of the total volume, compared to 60% in the average human.
4. Jellyfish are formed from polyps
Like many animals, the life cycle of jellyfish begins with eggs, which are fertilized by males. After this, things get a little more complicated: what emerges from the egg is a free-swimming planula (larva) that looks like a giant slipper ciliate. The planula then attaches itself to a solid surface (sea floor or rocks) and develops into a polyp resembling miniature corals or sea anemones. Finally, after several months or even years, the polyp detaches and develops into an ether, which grows into an adult jellyfish.
5. Some jellyfish have eyes
Cobojellyfish have a couple of dozen light-sensitive cells in the form of an eyespot, but unlike other marine jellyfish, some of their eyes have a cornea, lenses and retina. These compound eyes are arranged in pairs around the circumference of the bell (one pointing upward and the other downward, providing a 360-degree view).
The eyes are used to search for prey and protect themselves from predators, but their main function is the correct orientation of jellyfish in the water column.
6. Jellyfish have a unique way of delivering venom.
As a rule, they release their venom during a bite, but not jellyfish (and other coelenterates), which in the process of evolution have developed specialized organs called nematocysts. When the jellyfish's tentacles are stimulated, enormous internal pressure is created in the stinging cells (about 2,000 pounds per square inch) and they literally explode, piercing the skin of the unfortunate victim to deliver thousands of tiny doses of venom. The nematocysts are so powerful that they can be activated even when the jellyfish is washed ashore or dies.
7. The sea wasp is the most dangerous jellyfish
Most people are afraid poisonous spiders and rattlesnakes, but the most dangerous animal on the planet for humans may be a species of jellyfish - the sea wasp ( Chironex fleckeri). With a bell the size of a basketball and tentacles up to 3m long, the sea wasp prowls the waters off Australia and Southeast Asia and has killed at least 60 people in the last century.
A slight touch of the tentacles of a sea wasp causes excruciating pain, and closer contact with these jellyfish can kill an adult in a couple of minutes.
8. The movement of jellyfish resembles the operation of a jet engine
Jellyfish are equipped with hydrostatic skeletons, invented by evolution hundreds of millions of years ago. Essentially, the jellyfish's bell is a fluid-filled cavity surrounded by circular muscles that spray water in the opposite direction of movement.
The hydrostatic skeleton is also found in starfish, worms and other invertebrates. Jellyfish can move along with ocean currents, thereby saving themselves from unnecessary effort.
9. One type of jellyfish may be immortal
Like most invertebrate animals, jellyfish have a short lifespan: some small species live only hours, while the most large species For example, the lion's mane jellyfish can live for several years. Controversially, some scientists claim that jellyfish species Turritopsis dornii immortal: adults are able to return to the polyp stage (see point 4), and thus an endless life cycle is theoretically possible.
Unfortunately, this behavior has only been observed in laboratory conditions, and Turritopsis dornii can easily die in many other ways (such as becoming dinner for predators or being washed up on a beach).
10. A group of jellyfish is called a “swarm”
Remember the scene from the cartoon Finding Nemo, where Marlon and Dory have to navigate their way through a huge cluster of jellyfish? Scientifically, a group of jellyfish consisting of hundreds or even thousands of individual individuals is called a "swarm". Marine biologists have noticed that large aggregations of jellyfish are being observed more and more often, and may serve as an indicator of sea pollution or global warming. Jellyfish swarms tend to form in warm water, and jellyfish are able to thrive in anoxic marine conditions that are unsuitable for other invertebrates of their size.
Since ancient times, people have known strange shapeless sea animals, to which they gave the name “jellyfish” by analogy with the mythological ancient Greek goddess Medusa the Gorgon. The hair of this goddess was a moving tuft of snakes. The ancient Greeks found similarities between the evil goddess and sea jellyfish with poisonous tentacles.
The habitat of jellyfish is all the salty seas of the World Ocean. There is only one known freshwater species of these sea creatures. Each species occupies a habitat limited to one body of water and will never be found in another sea or ocean. Jellyfish are either cold-water or heat-loving; deep-sea and those that stay near the surface.
However, such species swim near the surface only at night, and during the day they dive into the depths in search of food. The horizontal movement of jellyfish is passive in nature - they are simply carried by the current, sometimes over long distances. Due to their primitiveness, jellyfish do not contact each other in any way; they are solitary animals. Large concentrations of jellyfish are explained by the fact that the current brings them to places rich in food.
Due to the highly developed colorless mesoglea, the body of the “flower cap” jellyfish (Olindias formosa) looks almost transparent Types of jellyfish
More than 200 species of jellyfish are known in nature. Despite the primitiveness of the structure, they are very diverse. Their sizes range from 1 to 200 cm in diameter. The largest jellyfish is the lion's mane (cyanea). Some of its specimens can weigh up to 1 ton and have tentacles up to 35 m long.
Jellyfish are shaped like a disk, an umbrella, or a dome. Most jellyfish have a transparent body, sometimes with bluish, milky, or yellowish tints. But not all species are so inconspicuous; among them there are truly beautiful, bright colors: red, pink, yellow, purple, speckled and striped. There are no green jellyfish in nature.
Species such as Equorea, Pelagia nocturna, and Rathkea can glow in the dark, causing a phenomenon called bioluminescence. Deep-sea jellyfish emit red light, while those floating near the surface emit blue light. There is a special type of jellyfish (staurojellyfish) that hardly move. They are attached to the ground with a long leg.
The structure of jellyfish
The internal structure and physiology of jellyfish are uniform and primitive. They have one main hallmark– radial symmetry of organs, the number of which is always a multiple of 4. For example, a jellyfish umbrella can have 8 blades. The body of a jellyfish does not have a skeleton; it consists of 98% water. When thrown ashore, the jellyfish is unable to move and dries up instantly. Its consistency is similar to jelly, which is why the British called it “jelly fish.”
Body tissues have only two layers, which are connected to each other by an adhesive substance and perform different functions. The cells of the outer layer (ectoderm) are “responsible” for movement, reproduction, and are analogues of skin and nerve endings. The cells of the inner layer (endoderm) only digest food.
The outer part of the body of jellyfish is smooth, mostly convex, the inner (lower) shape resembles a bag. The mouth is located at the bottom of the dome. It is located in the middle and is very different in structure among different types of jellyfish. The umbrella is surrounded by hunting tentacles, which, depending on the species, can be either thick and short or thin, thread-like, and long.
What do jellyfish eat?
Jellyfish are predators; they consume only animal food (crustaceans, fry, small fish, caviar). They are blind and have no senses. Jellyfish hunt passively, catching with their tentacles the edibles that the current brings. The hunting tentacles kill the prey. This is done different ways.
This is the largest jellyfish in the world - the cyanea, or lion's mane (Cyanea capillata), its long tentacles can reach 35 m in length! Some types of jellyfish inject poison into the prey, others glue the prey to the tentacles, and others have sticky threads in which it becomes entangled. The tentacles push the paralyzed victim towards the mouth, through which undigested remains are then expelled. Interestingly, jellyfish living in the depths attract prey with their bright glow.
How do jellyfish reproduce?
Jellyfish have vegetative (asexual) and sexual reproduction. Externally, males are no different from females. Sperm and eggs are released through the mouth into the water, where fertilization occurs. After this, the larva (planula) develops. The larvae are not able to feed, they settle to the bottom and a polyp is formed from them. This polyp can reproduce by budding. Gradually, the upper parts of the polyp separate and float away; these are actually young jellyfish that will grow and develop.
Some species of jellyfish do not have a polyp stage. Young individuals are immediately formed from the planula. There are also species in which polyps are formed in the gonads, from which small jellyfish are born. Each egg cell in jellyfish produces several individuals.
Vitality of jellyfish
Although jellyfish do not live long - from several months to 2-3 years, their numbers are restored very quickly even after various disasters. Their reproduction rate is very high. Jellyfish quickly restore lost body parts. Even if they are cut in half, two new individuals are formed from the halves.
Interestingly, if such an operation is performed in at different ages jellyfish, then an individual of the corresponding developmental stage grows from the tissues. If you divide the larva, then two larvae will grow, and from the adult parts - jellyfish of the appropriate age.
Jellyfish swimming upside down Jellyfish and people
Some types of jellyfish pose a danger to humans. They can be roughly divided into two groups. Some cause allergies, while the venom of others affects the nervous system and can cause serious problems in the functioning of the muscles and heart, and in some cases, death.
To avoid putting yourself in danger, you should avoid touching jellyfish, both living and dead. In case of a burn, you should wash the injured area with water, or better yet, a vinegar solution. If the pain does not subside and there are complications, you should immediately call a doctor.
Titles: common jellyfish, aurelia eared, eared jellyfish, moon jellyfish.
Area: Pacific, Indian and Atlantic oceans.
Description: The common jellyfish (Aurelia auriata) is easily identified by its four horseshoe-shaped gonads. The body is in the form of a flat umbrella, gelatinous, 97.8-98.2% consists of water. Along the edges of the umbrella there are numerous short hollow tentacles and eight marginal bodies (rhopalia). Rhopalia are the sense organs of the jellyfish and determine its position in the water and the rhythm of the umbrella contractions. Four thickened oral arms, each with a central groove flanked by more diluted curled lips. By detecting infrasounds, rhopalia warn the jellyfish about the approaching storm and allow them to move away from it. The body is two-layered (consists of two layers of cells - ectoderm and endoderm), with a well-defined gelatinous mesoglea. The mouth is located in the middle of the lower side of the body, it leads into the pharynx, from which the intestinal cavity begins. Undigested remains are removed through the mouth. The nervous system of a jellyfish is more developed than that of polyps. In addition to the nerve plexus, which is most developed in the tentacles and on the underside of the umbrella, two nerve rings run along its edge. The gonads are located near the stomach or radial canals.
Color: the umbrella is colorless, and the “arms” and gonads are lilac, purple, reddish, pink or yellowish.
Size: umbrella diameter 5-40 cm.
Habitat: near the coast - warm and tropical waters. Tolerates a wide range of temperatures (from -6 to 31"C) and salinity (from 6 ppm). Optimal temperature 9-19"C.
Enemies: moon fish, Pacific jellyfish, sea turtles, birds.
Food/food: intra- and extracellular digestion. The common jellyfish captures prey with its tentacles. Preys on planktonic crustaceans, aquatic insect larvae, fish fry, hydromedusas, ctenophores, copepods, rotifers, nematodes, young polychaetes, protozoa, and diatoms.
Behavior: It moves in water according to a reactive principle, pushing water out of the body cavities. The jellyfish swims horizontally in the water column.
Social structure: single organism.
Reproduction: the common jellyfish reproduces sexually. Jellyfish with purple or pink gonads are males, and those with yellow gonads are females. Male reproductive products are released through the mouth into the water, after which they enter the body of the female, where fertilization occurs. The egg develops into a mobile larva - a planula, which attaches to underwater objects and there turns into a single polyp. The polyp subsequently begins asexual reproduction. It breaks into several disks, which turn into jellyfish. This is how jellyfish alternate generations: asexual (polyp) and sexual (jellyfish). IN life cycle The jellyfish form predominates, and the polyp is a short-term form of existence.
Breeding season/period: in the fall.
Puberty: about 2 years.
Offspring: From fertilized eggs, larvae are formed - planulae, covered with cilia.
Benefit/harm for humans: The common jellyfish eats fish fry. In Asian countries (China, Philippines, Thailand, Malaysia, and Indonesia) it is used as food.
Population/Conservation Status: the population is large.
